#! /bin/sh
### BEGIN INIT INFO
# Provides:          prometheus
# Required-Start:    $local_fs $remote_fs
# Required-Stop:     $local_fs $remote_fs
# Default-Start:     2 3 4 5
# Default-Stop:      S 0 1 6
# Short-Description: Prometheus monitoring system
# Description:       The Prometheus monitoring system and time series database. https://prometheus.io/
#
### END INIT INFO

# Do NOT "set -e"

# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/usr/sbin:/usr/bin:/sbin:/bin:{{ prometheus_bin_path }}
DESC="Prometheus"
NAME=prometheus
DAEMON={{ prometheus_bin_path}}/$NAME
PIDFILE=/var/run/$NAME/$NAME.pid
DAEMON_ARGS="--config.file {{ prometheus_config_path }}/{{ prometheus_config_file }} \
    --web.listen-address {{ prometheus_listen_address }} \
    {% if prometheus_release_tag == 'latest' or prometheus_release_tag | regex_replace('^v(.*)$', '\\1') is version_compare('2.0.0', '>=') -%}
    --storage.tsdb.path {{ prometheus_tsdb_path }} \
    --storage.tsdb.retention {{ prometheus_tsdb_retention }} \
    {% else -%}
    --storage.local.path {{ prometheus_tsdb_path }} \
    --storage.local.retention {{ prometheus_tsdb_retention }} \
    {% endif -%}
    --log.level {{ prometheus_log_level }} \
    {{ prometheus_additional_cli_args }}"
USER={{ prometheus_user }}
GROUP={{ prometheus_group }}
SCRIPTNAME=/etc/init.d/$NAME

# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
[ -f /etc/default/rcS ] && . /etc/default/rcS

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

#
# Function to create run directory
#
mkrundir() {
        [ ! -d /var/run/prometheus ] && mkdir -p /var/run/prometheus
        chown $USER:$GROUP /var/run/prometheus
}

#
# Function that starts the daemon/service
#
do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    mkrundir
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --chuid $USER:$GROUP --background --make-pidfile --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --chuid $USER:$GROUP --background --make-pidfile -- \
        $DAEMON_ARGS \
        || return 2

    for i in `seq 1 30`; do
        if ! start-stop-daemon --quiet --stop --test --pidfile $PIDFILE --exec $DAEMON --user $USER --group $GROUP; then
            RETVAL=2
            sleep 1
            continue
        fi
        if "$DAEMON" info ${RPC_ADDR} >/dev/null; then
            return 0
        fi
    done
    return "$RETVAL"
}


#
# Function that stops the daemon/service
#
do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME
    RETVAL="$?"
    [ "$RETVAL" = 2 ] && return 2
    # Wait for children to finish too if this is a daemon that forks
    # and if the daemon is only ever run from this initscript.
    # If the above conditions are not satisfied then add some other code
    # that waits for the process to drop all resources that could be
    # needed by services started subsequently.  A last resort is to
    # sleep for some time.
    start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
    [ "$?" = 2 ] && return 2
    # Many daemons don't delete their pidfiles when they exit.
    rm -f $PIDFILE
    return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
    #
    # If the daemon can reload its configuration without
    # restarting (for example, when it is sent a SIGHUP),
    # then implement that here.
    #
    /bin/kill -HUP $PIDFILE
    return 0
}

case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  reload|force-reload)
    #
    # If do_reload() is not implemented then leave this commented out
    # and leave 'force-reload' as an alias for 'restart'.
    #
    log_daemon_msg "Reloading $DESC" "$NAME"
    do_reload
    log_end_msg $?
    ;;
  restart)
    #
    # If the "reload" option is implemented then remove the
    # 'force-reload' alias
    #
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  status)
      status_of_proc -p $PIDFILE $DAEMON $NAME && exit 0 || exit $?
      ;;
  *)
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac

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